Federal Opposition Leader Tony Abbott says it is typical of Labor that someone within the Prime Minister's office was tasking ministerial staff with digging dirt on the Coalition.

Labor sources say a few weeks ago Julia Gillard's director of strategy, Nick Reece, distributed an 11-point list on what information ministers' offices should gather on their Coalition opponents.

He also sent out a two-page spreadsheet on where to get the information.

The document asks ministerial staffers to dig up details on political opponents' "younger days", social media posts, articles in student newspapers, and past and present litigation.

Labor ministers have also been told to be on a campaign footing from next month amid a period of intensifying political attacks inside and outside Parliament.

There is disquiet within Labor ranks about the request, with one member of the Government telling AM it is aimed at "looking for shit on Labor's opponents".

The Labor MP described Mr Reece's office as "a dirt unit," saying such activities should not be associated with the Prime Minister's office.

Ms Gillard says she has not seen the document, but she is defending taxpayer-funded information-gathering on Labor's political opponents, saying it is a reasonable and legitimate part of the political process to scrutinise Opposition frontbenchers.

Mr Abbott says the Government is "seriously ethically challenged", but says he is not surprised by the latest revelations.

"It is typical of this government that a dirt unit should be operating, not somewhere in the bowels of Labor Party headquarters, but in the office of the Prime Minister herself," he said.

"Operating in her office, under her nose. No doubt with her express and enthusiastic participation."

Greens Senator Bob Brown says political dirt files are disgusting, and he says the tactic is wrong.

"I'm disgusted by them, I've never kept any," he said. "I know Eric Abetz has got one this big on me. And the Opposition is shameless in it, but I think people are pretty sick of it out there."

'Inappropriate' behaviour

Liberal backbencher Jamie Briggs, who chairs the Coalition's Scrutiny of Government Waste Committee, is pursuing what he claims is an inappropriate information-gathering activity by the Immigration Department, tracking a letter he wrote to the local newspaper.

"The letter to the local paper was in response to a criticism from a local Greens activist," he said.

"It had nothing to do with the policy and made no new point that I hadn't made before, which is that we will shut it down because we have a different way of dealing with the boat situation.

"You have to wonder why are they collecting this information? What is the purpose of this information other than in effect, spying on political opponents of the Government.

"Now that is a complete inappropriate use of public resources."

Mr Briggs worked for the Howard government, and concedes that government also collected information on ministers and backbenchers.

But he says that type of information-gathering was different.

"There has been allegations of dirt units in the past, but I think in the past what has happened was that information was kept to fight the battle of ideas, which of course is what our Parliament is for and that is appropriate," he said.

"People should be held to account for what they say in relation to policy issues but when it starts to dig in relation to specific individuals and their backgrounds and personal information, that is very questionable behaviour and it is very questionable when the public service, the apolitical public service, is being used to try and further political advantage for one party over another."

Mr Reece has tendered his resignation, and will leave next month to take up a job in academia.